Rifle grenade



E. W. BRANDT RIFLE' GRENADE Dec. 4, 1956 2 Sheets-Sheet 1 E, M BRANDT JNVENToR.

BY 411mm, m//lfa klm' Filed Aug. 17, 1953 Dec. 4, 1956 Filed Aug. 17, 1953 Fig. 6

E. W. BRANDT RIFLE GRENADE 2 Sheets-SheetI 2 E. MBANDT INVENTOR.

BY fm, www

nited tates PatentV RIFLE GRENADE Edgar William Brandt, Geneva, Switzerland, assiguor to Societe Anonyme Belge de Mecanique et dArmement, Brussels, Belgium, a corporation of Belgium Application August 17, 1953, Serial No. 374,532

Claims priority, application Luxemburg September 15, 1952 2 Claims. (Cl. 102-65.2)

This invention relates to a rifle grenade of the hollow charge type, provided with a base fuze.

Existing hollow charge projectiles are equipped either with a head fuze in which the transmission of tire vi-s effected through the hood, or perforatng cone open at its apex, to a detonator housed in the explosive charge, or with a base fuze operating by inertia on impact on the target and disposed behind the perforating cone, the apex of which is then closed.

Nevertheless, apart from their inferior properties as regards instantaneity of operation, fuzes of the second type had hitherto disadvantages both from the point of view of their sensitivity, and as regards their safety and the regularity of their operation.

Existing base fuzes were in fact provided with an inadequate safety device consisting of a pin, which is drawn out by'hand at the moment of action and which consequently considerably slowed down the rate of fire. VDevices of this type furthermore impaired the tightness of projectiles, Moreover, in the form in which they were constructed, the accidental explosion lof a base detonator invariably entailed the explosion of the projectile.

The present invention aims at obviating the aforementioned disadvantages, but also at providing a base fuze of great sensitivity, proof against shocks both in the course of transport and handling and in the event of the projectile being dropped on its head or on its tail, and in which the accidental explosion of the detonator, for any accidental reason, cannot effect the explosion of the explosive charge.

'I'he rie grenade of the present invention is fired with the aid of a launcher xed at the end of the weapon. Said grenade comprises a hollow explosive charge inside a charge carrier body, the cavity of said charge-being lined with a metallic cone, a finned tail at the rear of said body stabilizing the grenade on its trajectory, a base fuze functioning by inertia, and a delayed arming safety device.

The characteristic feature of the invention is that said fuze is housed Vin an intermediate chamber disposed between the charge carrier body and the tail of the grenade, the safety device retaining the detonator, before arming, in said chamber in the inoperative position and outside the charge, the detonator being adapted to pass, after the firing of the shot and under the effect of positive acceleration freeing the safety device, into the operative position in a hollow in the explosive charge which is provided for the purpose and at the bottom of which a striker is rigidly held, a spacing member interposed between the detonator and said striker causing the latter to yield on impact.

Rie grenades corresponding to this construction may then be transported and handled in full safety, their detonator being in the inoperative position. It is no longer necessary to perform any manual operation in order to arm the fuze, since the arming device remains locked not only up to the moment of firing, but also for a certain distance after the firing of the shot, being then autoice matically released and thus providing elective muzzle safety, preventing the explosion of the projectile in the event of its hitting an obstacle before that distance has been passed.

In one embodiment of the invention, said intermediate chamber has an extension projecting into the tail of the projectile and adapted to penetrate inside the tiring tube when the grenade is placed in position at the time of firing. A considerable reduction of the size of the base fuze is obtained in this manner.

According to another feature, the extension of said chamber has at its rear part an increased wall thickness provided to withstand the eiects of shock which may be produced under the action of the residues, Waste matter, etc. thrown by the gases of the cartridge on to said base.

The spacing member interposed between the detonator and the striker may be either a spring or, for preference, a hollow cylindrical piece the cavity of which widens out from rear to front and is obturated at its greatest aperture by a mat, which first comes into contact with the striker under the action of negative acceleration, and is then perforated by said striker at the moment of impact.

According to a further feature of the invention a cylindrical cushion, constituted by an inert material (parain wax, cardboard, ock, or the like) may advantageously be interposed between the striker and the apex of the hood. The result of this construction is that, in the event of the tirer inadvertently using a ball cartridge, the grenade can be perforated right through without exploding, since at no point :of its path will the ball be in contact with the explosive, kand the explosion of the detonator in its position outside the charge cannot entail the explosion of the grenade.

The deferred arming safety device has according to the rst modification of the invention an annular inertia member adapted to yield under the effect of positive acceleration against the action of an elastic member bearing against a second inertia member disposed behind the first, the two inertia members then becoming integral with one another by mechanical action (friction, de-

formation, crimping, interpenetration, and the like), said inertia members sliding towards the front after cessation of the acceleration on the firing of the shot and freeing one or more locking means, for example balls, which can then escape into a suitable housing and permit the passage of the detonator, in the operative position, into the explosive charge of the grenade.

The displacement of the detonator can be effected by counter-acceleration due to the resistance of the air on the projectile, to which action there may if desired be added that of a spring disposed between the detonator and the base of the chamber containing it.

Where desired, the arming of the fuze may Ibe further delayed with the aid of a slide integral with the second inertia member and guided in a Zig-zag groove.

According to another modification, the aforesaid inertia members may be concentric, the withdrawal of the first freeing a preliminary locking member, which then permits the forward `displacement of the 4Second inertia member.

Alternatively one of the aforesaid inertia members may be omitted, the single inertia member being constrained to perform a reciprocating movement by a xed slide penetrating into a groove having two branches provided at the periphery of said inertia member.

In the accompanying drawings, given solely by way of example:

Figure l is a view with partial axial section of a rie grenade according to the invention;

Figure 2 shows on a larger scale an axial section of the base fuze off the grenade shown in Figure l;

Figure 3 .is a cross-section .on the line 3-3 in Figure 2;

envases Figure 4 shows a detail of construction of the tiuze illustrated in vFigure 2;

Figure 5 shows a modified construction of the base fuze; l

Figure A6 is Ia detail of construction of the fu'ze villustrated in Figure 5 Figure 7 is a second modiieati'oh of said fuze;

Figure 8 shows a detail of construction of the fu'zie shown in Figure 7.

The rie grenade illustrated in Figure l comprises a ballistic cap 1, a body 2, a hollow explosive charge 3 the cavity of which is lined with a metallic cone 4, and

a tubular tail 5 carrying at its end stabilising ns 6. The base lfuze of the projectile is housed in `an intermediate chamber 7' between the charge `carrier body 2 'and the ltail 5. In the inoperative `position the detona'tor 8 is held in an extension 9 'of said chamber projecting into the tubular tail `5, a peripheral space 10 being provided between the w-all of the tail 5 and that of 'the extension 9 in 'order lto permit the penetration of the` tiring tube 11 (shown in broken lines in Figure v2). The baiseof the 'extension 9 has an increased wall thickness 12 adapted to Vresist the action yof the cartridge gases.

In the 'operative position the de'tonato'r 8 is housed in a hollow in thc explosive charge, 'at Ythe bottom of which hollow a striker 1'4 withits point facing rearwards .is held opposite a hollow cylindrical piece 15 obturated at its ront end by a mat 16 and placed at Vthehead o f 'the deton'ator 8, wit-h which it is united. A cylindrical cushion 26, for example of para'n wax, is interposed ybetween the striker 14 and the apex of the hood 4.

The safety device comprises two annular inertia members, of which, one, 17 is held in the forward position by Ia spring 18 Abearing on the other inertia member 19 which, when at rest, compresses a second spring 20.

The inertia member 17 is provided at its rear part and on its .periphery with claws 13 adapted to be crimped, on moving back on the tiring of the shot, in an annular groove in the inertia member 19. Two slides 21, held in the inertia member 19, are each guided in a zig-zag groove 22 (Figure 4) in the fixed sleeve 23. Two balls 24 (Figure 3), placed in Vorifices in the sleeve 22 and diametrically opposed, lock the piece 15 by bearing on an oblique 'circular 'bearing surface on the latter and hence lock the detonator 8 `which is thus held back of the charge. y

In Figure 5 the inertia members 17a and 19a are concentric -aud the first (17a) under the action of the spring a locks in position a ball 25 which locks the second inertia member 19a.

In the embodiment illustrated in Figure 7, Ia single inertia member 19b is suicient to elect the locking of the Aballs 24; its periphery has two grooves 22h, each having two branches. A lixed slide 2lb penetrates into each of the grooves, obliging the inertia member to follow the sinuositis of each of said branches.

The functioning of the fuze shown in Figure 2 is as follows: O n `the tiring of the shot, the inertia member 17 moves backwards during the positive acceleration of the projectilevagainst the action of the spring 18 and its elaws 4 13 are crimped -in a peripheral groove in the inertia 'member 19. The yinertia members 17 aid`1`9 which have become attached to one another are then pushed forward by counter-acceleration land under the action of the spring 20, which until that time was compressed. In their displacement, said inertia members fol-low 4the sinuosities of the groove 22, guided by the slide 21, while the balls 24A pushed |b`y vthe piece 15 mounted at the head 'of the deicnmr 8 escape. The demandes being freed, passes into the operative p'ositionrand slides forward by negatiie acceleration until w'the striker V14 makes ycontact withthe mat 16. j

When the projectile strikes vthe target the mat 16 bursts and the detonator 8 `is Vthrown on to the striker 14, thereby etecting the explosion of the 'detonator and that of the explosive change. l u n Y In the embodiment illustrated in Figure 5, the inertia member 17a moves backwards on the tiring of theshot, freeing'th'e b'all 25, which until Vthat moment had locked Athe concentric inertia member 19a. The two inertia mem; bers then rmove forwards through counteracceleration andunder the thrust of the spring 20a. 'Ile remainder offthe operation is the Vsame as previously.- K

'In Figure 7 Ythe inertia member `1917 elects alone,'by :a reciprocating movement, the unlocking of they balls 24A, the arming delay being achieved by the action of the slide `2lb which obliges vthe inertia member to follow the sinuosities of each of the branches 'of the groove 22b.

What is claimed is:

1. A rie grenade adapted to be tired from ka launcllei xed 'at the end of a rearm, said grenade comprising a charge carrier body, an explosive charge Ain said carrier body, a van'ed tubular tail at the 'rear of said bodyto stabilize vthe grenade on its trajectory, an axial and cylindricalchamber in the rear of said body, the front part of said chamber being in said charge and the vrear partof the chamber extending rearwardly an equal distancewin said tail, providing a peripheral space between the rear part of said chamber and the internal Wall of ksaid to receive the end part of said launcher, a striker carried the front part of said chamber, an inertia base fuse in side said chamber, said fuse including a detonator lodged in the projecting part of said chamber when in inoperative position, and a rsafety device for retaining the xdetonator in inoperative position, the total length ofrsafid chamber beirig at least twice the length ofvsaid detonator.

2. A rie grenade as claimed in claim 1, ,in which the diameter of at least a part of the external wall of said chamber is equal to the internal diameter of said launcher.

.References Cited in the tile of thisvpatent UNiT'ED STATES PATNTs I naamw. 

